Camera for industrial image processing

ABSTRACT

A camera for industrial image processing having a camera module and an objective module that is releasably connected thereto and has an optical system having at least one optical lens preferably comprises—in the camera module—an image sensor for capturing an image and a camera control unit for controlling the camera module and/or the objective module, and—in the objective module—a storage unit having lens data, wherein interacting wireless near field communication units are provided in the camera module and in the objective module, wherein the near field communication unit in the objective module converts an electromagnetic alternating field emitted from the near field communication unit in the camera module into electrical energy for supplying energy to the objective module, and the camera module reads the lens data out via the near field communication units, and the camera control unit controls therewith a function of the camera module and/or of the objective module.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119(a) ofAustria Patent Application No. A50838/2016 filed Sep. 19, 2016, thedisclosure of which is expressly incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a camera for industrial imageprocessing, having a camera module and an objective module releasablyconnected thereto, with an optical system having at least one opticallens, and to a method for operating such a camera for industrial imageprocessing.

2. Discussion of Background Information

In industrial image processing, for example, for machine visionapplications, it is common to use camera systems which have a cameramodule having an image sensor and an objective module (also simplycalled an objective) having a lens assembly (at least one optical lens)that are configured so as to be mechanically separated and releasablefrom one another. This makes it possible to use a camera module with avariety of interchangeable objectives. The mechanical connection betweenthe camera module and the objective module is then usually performedwith standardized objective mounts, such as, for example, a knownS-mount, C-mount, or CS-mount. The difference between these mounts lies,in addition to the different optical performance data thereof,substantially in the installation size. An S-mount uses an M12 thread,whereas a C- or CS-mount uses a 1″ thread having a pitch of 1/32″.Another difference is the flange focal distance, i.e., the predetermineddistance between the image plane of the image sensor and the fasteningsurface of the objective. DE 10 2012 111 231 A1 and WO 2010/081060 A1illustrate, for example, a camera for industrial image processing withwhich a variety of objectives, even with different mount systems, can bemounted. This does make it possible or easier to switch betweendifferent mount systems, it being only incumbent on the user to ensurethat all of the changes associated with switching the objective moduleare considered and implemented, which may be quite complicated andtedious. A different objective module, even if the focal length andaperture are identical, may necessitate changing the program settings ofdownstream image processing or camera parameters in the camera system,due to, for example, different optical properties. Another problemconnected thereto is that an objective module may be easily mistaken bythe user, possibly resulting in malfunctions of the machine visionsystem.

In many applications of industrial image processing, an objective havinga fixed focus or manually adjustable focus is used. With the manuallyadjustable variant, the objective, or the lens in the objective, isdisplaced relative to the image sensor in the camera module by aspecific mechanism, for example, via a rotatable adjusting ring. Suchobjectives are also disclosed in DE 10 2012 111 231 A1 and WO2010/081060 A1. Also known are solutions with which the objective isdisplaced relative to the image sensor by screwing or unscrewing themount thread into the camera module, or by adjusting by means of athread separation in the objective, which also amounts to focusadjustment. The position of the objective is then fixed, for example, bymeans of a lock nut or a blind set screw, in order to fix the focussetting. Other known objectives have a motorized focus adjustment, suchas in, for example, U.S. Pat. No. 6,172,709 B1. Due to the small size ofobjectives that is especially sought after for industrial imageprocessing, however, these solutions are very costly. There is also thefact that these would not be suitable for frequent focus adjustment—suchas would be necessary, for example, with autofocus in many applicationsof industrial image processing with, typically, several thousand imagesper minute—due to the adjustment speeds required and the short servicelives. Another problem with motorized focus adjustment is the electricalenergy supply necessary therefor, which is generally implemented via thecamera module and electrical contacts.

There are also known objectives for industrial image processing that useliquid lenses that enable automatic focus adjustment, also as autofocus.The problem with liquid lenses is primarily the required electricalenergy supply for the liquid lenses and the electronics for controllingthe liquid lens. The electrical energy supply and the control areperformed in most cases via the camera module, via electrical contactsbetween the camera module and the objective module for the energy supplyand the control. Examples thereof are also disclosed in DE 10 2012 111231 A1 or WO 2010/081060 A1. In these examples the electrical contactwith the camera module is prepared afterwards, for example, in the caseof a connection cable that is plugged into provided sockets after theobjective has been connected to the camera module. Both, however,necessitate corresponding provisions, such as contacts, plugs, sockets,cables, and the like, making the camera system more complex and moreerror-prone. It is even common to make a plurality of provisions at thesame time, due to the absence of any standardized mount, on account ofthe large number of mounting methods for contacting liquid lenses, evenwith different objective modules from the same manufacturer. Electricalcontacts do, however, also have the disadvantage, especially in thefield of industrial image processing, that they are prone to fouling ofaccessible contacts in the industrial environment. This remains aproblem even when plugs and sockets are used, such as is described, forexample, in DE 10 2012 111 231 A1.

Cameras from the consumer goods sector, such as conventional photo orvideo cameras, generally have objectives with auto focus adjustment,wherein the electrical energy is also provides via electrical contactsbetween the camera module and the objective. These objectives aregenerally of very complex construction, are expensive and generally alsotake up a much larger space due to other connections. The number ofimages taken within a typical life cycle with such cameras is also muchlower than with applications in industrial image processing, whichallows for mechanical solutions for focus adjustment. The above problemstherefore do not occur with such cameras. In this area, however, it isusually such that each manufacturer has defined their own mount, andthese are not compatible with one another. Cameras from the consumergoods sector are also unsuitable for industrial image processing,because such cameras are not available in variants suitable forindustrial applications. This means that they neither meet therequirements for environmental conditions (temperature, vibrations,tightness requirements, etc.), nor possess, apart from the standardizedstand thread, suitable options for mechanical mounting onto a machine oran industrial interface to communicate with a control device or anexternal peripheral. These cameras often have neither an interface forraw image transmission to an external image evaluation unit, nor offerthe option of internal image processing on the camera for applicationsin industrial image processing. In addition, such cameras also generallyoffer no possibility for triggering or synchronizing within themicrosecond range, commonly required for industrial applications. Forthese reasons, such cameras from the consumer goods sector are virtuallyunusable in the field of industrial image processing.

U.S. Pat. No. 5,630,180 A also discloses a camera from the consumergoods sector that has an interchangeable objective. In theinterchangeable objective, a storage unit stores lens data that can beread out from the camera and is used in the camera to correct theoptical properties of the objective. The connection between theinterchangeable objective and the camera is made, once again, viaelectrical contacts having all of the aforementioned disadvantages.

Corrections for the changes of an optical system over time may, however,also be performed without saved lens data, such as is disclosed in, forexample, DE 10 2015 106 844 A1 for an industrial image processing systemhaving an interchangeable lens assembly. The interchangeable lensassembly comprises, in particular, a variable lens and a collecting lensassembly. The optical drift of a vision system that occurs over time iscompensated for with the variable lens. The electrical connectionbetween the lens assembly and the camera module takes place viaelectrical contacts, yet again with all of the aforementioneddisadvantages.

SUMMARY OF THE EMBODIMENTS

The present invention addresses the problem of setting forth a camerafor industrial image processing and a related method for operating acamera for industrial image processing that does not have theaforementioned disadvantages of the prior art.

This problem is solved according to the invention by providing, in thecamera module, an image sensor for capturing an image and a cameracontrol unit for controlling the camera module and/or the objectivemodule, by providing a storage unit that has lens data in the objectivemodule, and by also providing interacting wireless near fieldcommunication units in the camera module and in the objective module,wherein the near field communication unit in the objective moduleconverts electromagnetic waves emitted from the near field communicationunit in the camera module into electrical energy for supplying energy tothe objective module, the camera module reads out the lens data via thenear field communication units, and the camera control unit controlstherewith a function of the camera module and/or the objective module.The problem is also solved with a method in which, in the objectivemodule, a storage unit stores lens data that is read out from the cameramodule via interacting near field communication units in the objectivemodule and camera module and is used in a camera control unit in thecamera module, in order to capture an image with the camera, andelectrical energy for supplying energy to the objective module isobtained from the electromagnetic alternating field emitted from thenear field communication unit in the camera module.

These measures make it possible to overcome all of the disadvantagesassociated with electrical contacts on the camera module and objectivemodule. Because both the energy supply and the data communicationbetween the objective module and the camera module are transmitted vianear field communication, i.e., wirelessly, there is no need at all forthe objective module and camera module to have therebetween anyelectrical contacts that can be damaged, for example, when the objectiveis being switched and/or due to environmental influences. The storageunit in the objective module additionally makes it possible to save lensdata that can be used to control a function of the objective moduleand/or of the camera module.

The lens data may also, however, include data that makes it possible touniquely identify the objective module, so that mistaken use ofobjective modules can be practically eliminated or can be identified andindicated. It would also be possible to use, as lens data, data of theoptical system of the objective module that makes it possible to set,even automatically, camera parameters or program settings in the cameramodule that are required in order to capture an image. Last but notleast, correction data making it possible to compensate for aberrationsin the optical system may also be used as the lens data. The storageunit of the objective module may, however, also store operating datathat would be interesting for servicing. For example data on the maximumambient temperature, shock or vibration, or the operating time, arevaluable information that the objective module can store in the storageunit, either independently or via the camera module.

If the camera module also controls a function of the objective module,then it is advantageous when the camera module sends control data forcontrolling the objective module via the near field communication unitto the objective module. Thus, no electrical contacts are required forthis data transfer, either.

It is also especially advantageous when electrical energy for supplyingenergy to a variable-focus optical lens, e.g., a liquid lens, in theobjective module is obtained from electromagnetic waves emitted from thenear field communication unit in the camera module. The objective moduletherefore does not require any own energy supply, thus simplifying, inparticular, the handling of the objective modules as well.

With a sensor in the objective module, as well, it is very especiallyadvantageous to detect a physical quantity in the vicinity of theobjective module and use the physical quantity to control a function ofthe objective module and/or of the camera module. It is alsoadvantageous when the physical quantity is used to correct a dependenceof the optical properties of the objective module on this physicalquantity. With one of these measures, the camera is capable ofautomatically adapting itself to different installation locations anddifferent environmental conditions, whereby the quality of imagecapturing can be improved.

To correct the dependence, it would be possible to simply savecorrection data, which can easily be read out via the near fieldcommunication, as the lens data.

Due to the desired compactness, cameras for industrial image processingoffer little installation space, e.g., because the camera module and theobjective module are releasably connected to one another via astandardized C-mount, CS-mount, or S-mount connection. In order tonevertheless be able to accommodate the required antennas for the nearfield communication, it is advantageous when there is provided, on theobjective module, a lens flange that surrounds the optical system of theobjective module and abuts against an abutment surface on the cameramodule, wherein an antenna arrangement of the near field communicationunit of the objective module is arranged on the lens flange and anantenna arrangement of the near field communication unit of the cameramodule is arranged on the abutment surface. To this end, it isbeneficial when the antenna arrangement on the objective module isarranged in a depression of the lens flange, and/or the antennaarrangement on the abutment surface is arranged in a depression of theabutment surface. Thus, compliance with the flange focal distance of theoptics can be easily ensured, and yet a sufficiently large surface forthe energy transfer can also be made available. In configurations withlower energy requirements, for example, when no actuators and/or no oronly a few sensors need to be supplied, a rod antenna may also sufficein order to make the required energy available.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention shall be described in further detail hereinbelowwith reference to FIG. 1 to 3, which illustrate advantageous embodimentsof the present invention by way of example, in a schematic andnon-limiting manner. In the drawings,

FIG. 1 illustrates a camera module and an objective module of a camerafor industrial image processing according to the invention;

FIG. 2 illustrates components of the camera module and objective module;and

FIG. 3 illustrates a possible configuration of the connection betweenthe camera module and objective module.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 illustrates (in an exploded view) a camera 1 for industrial imageprocessing according to the invention, which comprises a camera module 2and an objective module 3. The camera module 2 and the objective module3 are releasably connected via a standardized mount 4, e.g., a C-mountor S-mount. The mount 4 is composed, for example, of an internal thread5 on the camera module 2 and a corresponding external thread 6 on theobjective module 3, which is screwed into the internal thread 5 of thecamera module 2. In the objective module 3, or in the housing of theobjective module 3, there is provided (see FIG. 2) an optical lens,e.g., a lens having a fixed focus or a variable-focus lens 31, such asfor example a liquid lens, or even a lens system composed of a pluralityof lenses (or a mixture of lenses having fixed and variable focus). Animage sensor 21 for digitally capturing an image is arranged in thecamera module 2, or in the housing of the camera module 2. There are noelectrical contacts between the camera module 2 and the objective module3, neither for electrical energy supply nor for a control connection.

An objective control unit 32 for controlling the variable-focus lens 31,such as the liquid lens, is optionally arranged in the objective module3. The objective control unit 32 is used to adjust the variable-focuslens and thus to adjust the focus of the camera 1. With a lens that hasfixed focus, the objective control unit 32 may be omitted undercircumstances, or the objective control unit 32 need not have thisfunctionality.

There are a variety of known configurations for a liquid lens. One knownvariant uses two isodense liquids, e.g. oil and water, that form aliquid-liquid interface in the lens. Applying different electricalvoltages to the lens makes it possible to alter the curvature of thisliquid-liquid interface, which, in turn, leads to a change in the focallength. Another known liquid lens uses a movable membrane that covers aliquid reservoir in order to vary the lens focus. The shape of themembrane is altered by means of a coil, through the application of anelectrical current, in order to vary the lens focus. The focus of theliquid lens is therefore adjusted through the application of anelectrical voltage or an electrical current.

An image processing unit 22 that processes and/or evaluates digitalimage data captured from the image sensor 21 is arranged in the cameramodule 2. The result of the processing may be outputted via an interface23. The interface 23 may be configured, for example, as a connection toa data bus. The image data itself could also be outputted via theinterface 23. Suitable image processing software is thereforeimplemented in the image processing unit 22. In the image processingunit 22, image processing algorithms by means of which a captured imagecan be pre-processed or edited may be implemented. The step, necessaryfor a machine vision system, of evaluating the image data, for example,in order to control a machine or installation therewith, then takesplace in an external unit, e.g., in a control unit of the machine orinstallation. This evaluation of the image data may also take placedirectly in the image processing unit 22, however, for which reasonsuitable algorithms or application software would then be implemented—inthis case, the term “smart camera” is also often used. A smart cameratherefore transmits control data to a machine or installation controldevice in order to control same. A camera control unit 24 that controlsthe camera 1 and optionally also a function of the objective module 3,e.g. by controlling the focus or an aperture adjustment, is alsoarranged in the camera module 2.

The objective module 3 also has provided therein a storage unit 33 thatstores lens data of the optical system, in the manner of an electronictype plate. This lens data may comprise, in particular, data foruniquely identifying an objective module 3, data about the opticalsystem or the optical lens of the objective module 3, and calibrationdata of the objective module 3. In the minimum case, a property of theoptics or the lens is stored, in particular, the focal length andoptionally also the aperture, in the case of an adjustable aperture alsothe minimum and maximum aperture. Examples of other lens data include aproduct designation (order number, product number), a serial number, atype designation, approved manufacturers of camera modules, theadjustment range of the focal lengths with a variable-focus lens, asupported image sensor diagonal, the aberrations of optics (e.g.,vignetting, distortion, etc.), and correction data for aberration of theoptics. Certain lens parameters, such as, for example, the distortion orthe marginal drop of illumination (relative illumination), may also bedetermined and used as lens data.

Operating the objective module 3, in particular, in order to read outthe lens data from the storage unit 33 requires electrical energy. Beingable to read out the lens data also necessitates data communicationbetween the camera module 2 and the objective module 3. According to theinvention, both the energy supply and the data communication take placevia near field communication (NFC) between the camera module 2 and theobjective module 3. For this purpose, a near field communication unit25, 35, respectively connected to an associated antenna arrangement 26,36, is arranged in both the camera module 2 and in the objective module3. The near field communication can then be implemented as bothactive/passive and active/active (peer-to-peer). The near fieldcommunication unit 35 in the objective module 3 obtains the energy forreading out from the storage unit 33 from the electromagneticalternating field of the near field communication that is emitted fromthe camera module 2.

The lens data can thus be read out from the camera module 2 via the nearfield communication, either directly or via the objective control unit32. The lens data may then be used in the camera module 2 in order toensure that only an objective module 3 that is suitable for the cameramodule 2 is being used. To this end, it is possible to use, for example,the type designation, the focal length and/or the image sensor diagonal.In this manner, errors in the image capture that may occur due todifferences even with the identical type of objective module 3 can beavoided. If these differences are known, for example, because they arestored in the storage unit 33, then these differences can be taken intoconsideration in the image processing in the image processing unit 22,or the image may already have been previously corrected. This preventsslight differences from causing sporadic errors in the industrial imageprocessing, the origin of which are difficult to assign or determine.

Correction data for aberrations of the objective module 3 (i.e., theentire optical system of the objective module 3) are preferablytherefore also stored as lens data. The aberrations or correction dataare collected, for example, when the objective module 3 is calibratedand are stored, for example, in the form of a calibration table in thestorage unit 33. The camera module 2 can read out the correction data,for example, if a new objective module 3 is being fastened onto thecamera module 2, and can then correct the captured image data with thecorrection data, which improves the quality of the image capture.

Electrical energy is also required for operating or adjusting avariable-focus lens 31, such as, for example, the liquid lens, or foradjusting an adjustable aperture 43 in the objective module 3. Controlcommands to the objective control unit 32 for adjusting thevariable-focus lens 31 in order to change the focus and/or for adjustingthe aperture may optionally also be exchanged by means of datacommunication between the camera module 2 and the objective module 3.Both take place via near field communication (NFC) between the cameramodule 2 and the objective module 3.

The near field communication also requires antennas in the camera module2 and in the objective module 3. The antenna arrangement 26 of thecamera module 2 may be arranged on a camera module abutment surface 8 inthe region of the mount 4. Likewise, the antenna arrangement 36 of theobjective module 3 may be arranged on an objective module abutmentsurface 7 in the region of the mount 4. The camera module abutmentsurface 8 and the objective module abutment surface 7 are then arrangedfacing one another, so that antenna arrangements 26, 36 arranged thereonare also arranged facing one another. The two antenna arrangements 26,36 are therein aligned with one another, as a matter of course, andarranged as close as possible to one another, in order to enablefavorable inductive coupling for the near field communication and theenergy supply. Surfaces on the camera module 2 and objective module 3that face each other are therefore especially suitable for theinstallation of the antenna arrangements 26, 36. The antennaarrangements 26, 36 preferably do not alter the optical system of thecamera 1, in particular, for example, the flange focal distance of theoptics should not be affected. The antenna arrangements 26, 36 aretherefore preferably arranged in depressions on the camera module 2 oron the objective module 3, respectively. An antenna arrangement 26, 36is preferably mounted on a printed circuit board 27, 37 that is insertedinto a depression on a surface of the objective module 3 or of thecamera module 2. A printed circuit board 27, 37 may also be configuredas a flexible printed circuit board, whereby the number of possiblearrangements is increased. This makes it possible to arrange the antennaarrangements 26, 36 as close to one another as possible with apredetermined and unmodified mount 4 (thread, flange focal distance). Inthe illustrated embodiment according to FIG. 2, the antenna arrangements26, 36 are arranged on annular printed circuit boards 27, 37 andrespectively arranged on end surfaces on the camera module 2 andobjective module 3 that face one another and abut against one another.The antennas of the antenna arrangements 26, 36 are preferably providedas spiral-shaped conductors on the printed circuit boards 27, 37.

A near field communication unit 25, 35, with the associated antennaarrangement 26, 36, may also be arranged in an own enclosed housing (aso-called transponder inlay 42 or RFID chip), which can then be insertedinto a corresponding recess on the camera module 2 or objective module3. The antenna arrangement 26, 36 of such a transponder inlay 42 reducesthen, as a matter of course, to the size of the transponder inlay 42. Ifa transponder inlay 42 is used in the objective module 3, then, forexample, a stub antenna or rod antenna of a corresponding size relativeto the transponder inlay is sufficient on the camera module 2. Atransponder inlay 42 often also offers an integrated storage unit 33,which may be used to store lens data. In this case, a separate,additional storage unit in the objective module 3 may even be omittedunder certain circumstances. It is also, however, conceivable to useboth a storage unit in the transponder inlay and an additional storageunit in the objective module 3 as the storage unit 33 in the objectivemodule 3. Examples of such transponder inlays 42 include a NeoTAG® Inlayfrom Industria Oberländer Ingenieur-GmbH & Co. KG or an RUD-ID-Point®from RUD Ketten Rieger & Dietz GmbH u. Co. KG. Such a transponder inlay42 offers, first and foremost, the advantage of a very compact size,which makes it especially suitable for use in an objective module 3.

A camera 1 for industrial image processing is preferably configured soas to be robust, for which reason the housing of the camera module 2and/or objective module 3 is often made of metal. In order to reduce anadverse effect on the near field communication from metallic surfaces,there may also be a shielding, for example, in the form of a ferritefilm or a ferrite shell 44, provided between an antenna arrangement 26,36 and the housing of the camera module 2 or objective module 3.

Other surfaces on the camera module 2 and objective module 3 that faceeach other are also suitable for installation of the antennaarrangements 26, 36. For example, the antenna arrangements 26, 36 couldalso be provided in the region of the threads 5, 6 of the mount 4.

The camera control unit 24 of the camera module 2 and the objectivecontrol unit 32 of the objective module 3 are therefore able tocommunicate with one another and exchange data via the near fieldcommunication units 25, 35 and the associated antenna arrangements 26,36. This also makes it possible, in particular, to control avariable-focus lens of the objective module 3 via the camera module 2,or to adjust an adjustable aperture 43 of the objective module 3. Thus,an auto focus function can be implemented even via the camera controlunit 24 and the evaluation of the image data in the image processingunit 22.

The electrical energy for operating the objective module 3, in additionto reading out from the storage unit 33, can also be obtained from thenear field communication. The energy of the electromagnetic alternatingfield emitted from the near field communication unit 25 of the cameramodule 2 via the antenna arrangement 26 can also be converted in thenear field communication unit 35 of the objective module 3 intoelectrical energy (an energy harvesting function of the near fieldcommunication) and used to operate the objective module 3. After theobjective module 3 requires only very little electrical energy tooperate, the electrical energy obtained from the near fieldcommunication is sufficient therefor. Thus, the objective module 3 doesnot require any electrical connection for additional supply ofelectrical energy. It shall be readily understood that there may also bea transponder inlay 42 used for energy harvesting, if there is asuitably small distance between the associated antenna arrangements 26,36.

The objective module 3 may also have arranged thereon at least onesensor 38 that detects a physical quantity in the environment of theobjective module 3, such as, for example, a temperature or the like.

The sensor 38 may also be read out from the camera module 2 via the nearfield communication unit 35, and the camera module 2 may use thedelivered sensor values to control the camera 1. The reading out fromthe sensor 38 may take place directly via the near field communicationunit 35, or also indirectly via the objective control unit 32 (such asin FIG. 2). For example, an illumination unit of a machine vision systemfor industrial image processing could be controlled via the detectedambient temperature. It may also be provided that a sensor value isoutputted via the interface 23.

An adjustable-focus lens 31, such as, for example, a liquid lens, mayhave optical properties that are dependent on the temperature, whereinthe temperature dependency is generally known, for example, bymeasurement or manufacturer specification. Temperature-dependentcorrections may be performed therewith, e.g., compensation for apossible temperature-dependent change of the optical properties of avariable-focus lens 31. For this purpose, the temperature is preferablymeasured close to the lens, for example, through a sensor 38, which maybe arranged in the objective module 3 close to the lens 31. Thetemperature dependency could then also be stored in the storage unit 33as lens data, for example, as a suitable characteristic map. Atemperature-dependent correction could then be implemented in theobjective module 3, e.g., in the objective control unit 32. If thecorrection takes place directly in the objective module 3, then thereis, as a matter of course, no need to read out the relevant lens datafrom the camera module 2. Such a temperature-dependent correction couldalso be implemented in the camera module 2, for example, in the cameracontrol unit 24 with which the optical system is controlled. It is alsoconceivable to perform the temperature-dependent correction later in thecamera module 2 via the image processing in the image processing unit22, provided that these temperature-dependent errors entail errors thatcan be corrected through software.

A position sensor 39 that collects, for example, the spatial angle tothe normal of the force of gravity may also be provided in the objectivemodule 3. The location of the camera module 2 or objective module 3 inthe space can thus be determined, set (even automated), and monitored.The position sensor 39 may also be configured as a gyro sensor, orcontain a gyro sensor, in order to be able to also detect an angularacceleration, in addition to a linear acceleration. The position sensor39 can thus always correctly determine the location in the space, evenif the camera 1 is moving, e.g., when mounted on a robot arm. Likewise,position- or acceleration-dependent corrections could also be performedtherewith. The properties of a variable-focus lens 31, such as, forexample, a liquid lens, may also be dependent, for example, on theinstallation position or an applied external acceleration (e.g., as adouble time derivative of the position, or also by means of anacceleration sensor), because the acceleration can cause so-called comaerror. This dependency is generally known, for example, by measurementor by manufacturer specification, and can therefore be stored, read out,and taken into consideration as lens data. Analogously to thetemperature-dependent corrections, there may also be position- oracceleration-dependent corrections performed in the objective module 3or in the camera module 2 by control of the optical system or throughsoftware in the image processing unit 22.

The position sensor 39 may also be read out from the camera module 2 viathe near field communication unit 35, and the camera module 2 may usethe delivered sensor values to control the camera 1 or output same viathe interface 23. The reading out from the position sensor 39 may takeplace directly via the near field communication unit 35 (such as in FIG.2), or also indirectly via the objective control unit 32.

In addition to temperature and position/acceleration, still otherphysical quantities in the environment of the objective module may alsobe detected, as a matter of course, such as, for example, the relativehumidity in the surroundings, because the optical system or a partthereof may also change in accordance therewith. Such a physicalquantity could then, in turn, be used to control a function of theobjective module 3 and/or the camera module 2, or to correct adependency of the optical properties of the objective module 3 on thisphysical quantity.

A distance sensor 45 that measures the distance of the objective module3 from a reference plane may also be provided in the objective module 3.Together with the position sensor 39, the relative position of theobjective module 3 in space relative to a reference plane can be checked(for example, in the camera module 2, or in a machine or installationcontrol device connected thereto), which can be used, for example, toadjust a machine vision system. The distance sensor 45 may also be usedto control the image capture and/or illumination of the industrial imageprocessing.

The distance sensor 45 may also be read out from the camera module 2 viathe near field communication unit 35, and the camera module 2 may usethe delivered sensor values to control the camera 1. The reading out ofthe distance sensor 45 may take place directly via the near fieldcommunication unit 35, or also indirectly via the objective control unit32 (such as in FIG. 2).

The sensor 38 and/or the position sensor 39 and/or the distance sensor45 could also, or additionally, be installed in the camera module 2,wherein the sensor values can then be read out, for example, directlyfrom the camera control unit 24 or the image processing unit 22. Thesensor 38 and/or the position sensor 39 and/or the distance sensor 45could also, or additionally, be installed on other suitable places thatare, however, uniquely associated with the objective module 3, forexample, on an illumination unit fixedly installed on the camera 1.Reading out from sensors installed in this manner can be performed, forexample, again by means of near field communication, or via a fixedwiring.

With very small objective modules 3, for example, in the case of anS-mount, the available installation size may, in certain circumstances,not suffice to arrange the elements required for the near fieldcommunication directly on the objective module 3. In particular in thiscase, a transponder inlay may be used on the objective module 3. Theremay also be provided an expansion ring 40, such as is depicted in FIG.3, that is threaded onto the thread 6 of the mount 4 of the objectivemodule 3. The antenna arrangement 36 and the associated near fieldcommunication unit 35 of the objective module 3, for example configuredas the transponder inlay 42, as in FIG. 3, may be arranged on theexpansion ring 40. There could also be provided antenna arrangements 26,36 that are arranged on annular printed circuit boards 27, 37 and arerespectively arranged on end surfaces on the camera module 2 andobjective module 3 that face one another and abut against one another,such as is depicted in FIG. 2. If sufficient energy, for example forcontrolling actuators, can be made available, for example, through thelarge-area connection of the annular arrangement, then the connection tothe objective control unit 32 and, subsequently, to the variable-focuslens 31 and to a sensor 38, or also to a position sensor 39 or distancesensor 45, can already be implemented at the manufacture of theobjective module 3, via a suitable interacting electrical connection 41on the objective module 3 and on the expansion ring 40. The electricalconnection 41 could then also be implemented as a permanent connection.The expansion ring 40 and the objective module 3 may then be threadedtogether into the camera module 2. Still no electrical contacts in theform of plug-in connections are required at all between the cameramodule 2 and the objective module 3 (with the expansion ring 40).

The storage unit 33 of the objective module 3 or of the expansion ring40 may, however, also store operating data that would be interesting forservicing. Thus, for example, data on the maximum ambient temperature,shock, or vibration, or the operational duration, which may be obtained,for example, from the built-in sensors in the objective module 3, isvaluable information. Such operational data may be read out from orwritten to the storage unit 33 of the objective module 3 by theobjective module 3, either independently, for example via the objectivecontrol unit 32, or via the camera module 2 and the near fieldcommunication unit 35, and may be outputted, for example, from thecamera module 2 to a display, or can be read out via the interface 23.

1. A camera for industrial image processing, comprising a camera module(2) and an objective module (3) that is releasably connected thereto andhas an optical system having at least one optical lens, wherein an imagesensor (21) for capturing an image and a camera control unit (24) forcontrolling the camera module (2) and/or the objective module (3) areprovided in the camera module (2), and a storage unit (33) having lensdata is provided in the objective module (3), wherein interactingwireless near field communication units (25, 35) are provided in thecamera module (2) and in the objective module (3), wherein the nearfield communication unit (35) in the objective module (3) converts anelectromagnetic alternating field emitted from the near fieldcommunication unit (25) in the camera module (2) into electrical energyfor supplying energy to the objective module (3) and wherein the cameramodule (2) reads the lens data out via the near field communicationunits (25, 35) and the camera control unit (24) controls therewith afunction of the camera module (2) and/or of the objective module (3). 2.The camera according to claim 1, wherein the camera module (2) sendscontrol data for controlling the objective module (3) to the objectivemodule (3) via the near field communication units (25, 35).
 3. Thecamera according to claim 1, wherein a variable-focus optical lens (31)is provided in the objective module (3), wherein the near fieldcommunication unit (35) in the objective module converts theelectromagnetic alternating field emitted from the near fieldcommunication unit (35) in the camera module (2) into electrical energyfor supplying energy for the adjustment of the variable-focus opticallens.
 4. The camera according to claim 3, wherein the adjustable opticallens (31) is a liquid lens.
 5. The camera according to claim 1, whereinan adjustable aperture (43) is provided in the objective module (3),wherein the near field communication unit (35) in the objective module(3) converts the electromagnetic alternating field emitted from the nearfield communication unit (25) in the camera module (2) into electricalenergy for supplying energy for the adjustment of the adjustableaperture (43).
 6. The camera according to claim 1, wherein an objectivecontrol unit (32) that is connected to the near field communication unit(35) in the objective module (3) is provided in the objective module(3), wherein the objective control unit (32) receives control commandsfrom the camera module (2) via near field communication.
 7. The cameraaccording to claim 1, wherein an objective module abutment surface (7)is provided on the objective module (3), that faces a camera moduleabutment surface (8) on the camera module (2), wherein an antennaarrangement (36) of the near field communication unit (35) of theobjective module (3) is arranged on the objective module abutmentsurface (7) and an antenna arrangement (26) of the near fieldcommunication unit (25) of the camera module (2) is arranged on thecamera module abutment surface (8).
 8. The camera according to claim 7,wherein the antenna arrangement (36) on the objective module (3) isarranged in a depression of the objective module abutment surface (7),and/or the antenna arrangement (26) on the camera module (2) is arrangedin a depression of the camera module abutment surface (8).
 9. The cameraaccording to claim 1, wherein the camera module (2) and the objectivemodule (3) are releasably connected to one another via a standardizedC-mount, CS-mount, or S-mount connection.
 10. The camera according toclaim 1, wherein at least one sensor for detecting a physical quantityin the environment of the camera (1) is arranged in the objective module(3) and/or in the camera module (2).
 11. The camera according to claim10, wherein the near field communication unit (35) in the objectivemodule (3) converts the electromagnetic alternating field emitted fromthe near field communication unit (25) in the camera module (2) intoelectrical energy for operating and reading out from the sensor.
 12. Thecamera according to claim 10, wherein a temperature sensor (38) isarranged as a sensor.
 13. The camera according to claim 12, whereincorrection data for correcting a temperature dependency of the opticalsystem of the objective module (3) is stored in the lens data.
 14. Thecamera according to claim 13, wherein the correction of the temperaturedependency is implemented in the objective module (3) or in the cameramodule (2).
 15. The camera according to claim 10, wherein a positionsensor (39) and/or a distance sensor (45) is/are arranged as a sensor.16. The camera according to claim 15, wherein correction data forcorrecting a position dependency and/or acceleration dependency and/ordistance dependency of the optical system of the objective module (3) isstored in the lens data.
 17. The camera according to claim 16, whereinthe correction of the position dependency and/or acceleration dependencyand/or distance dependency is implemented in the objective module (3) orin the camera module (2).
 18. The camera according to claim 1, whereindata for uniquely identifying the objective module (3) is stored in thelens data.
 19. The camera according to claim 1, wherein data on theoptical system of the objective module (3) is stored in the lens data.20. The camera according to claim 1, wherein calibration data on theobjective module (3) is stored in the lens data.
 21. A method foroperating a camera (1) for industrial image processing, wherein thecamera (1) comprises a camera module (2) and an objective module (3)that is releasably connected thereto and has an optical system having atleast one optical lens, wherein in the objective module (3) lens datathat is read out from the camera module (2) via interacting near fieldcommunication units (25, 35) in the objective module (3) and cameramodule (2) is stored in a storage unit (33) and used in a camera controlunit (24) in the camera module (2) in order to capture an image with thecamera (1) and wherein electrical energy for supplying energy to theobjective module (3) is obtained from the electromagnetic alternatingfield emitted from the near field communication unit (25) in the cameramodule (2).
 22. The method according to claim 21, wherein the cameramodule (2) sends control data for controlling the objective module (3)to the objective module (3) via the near field communication units (25,35).
 23. The method according to claim 21, wherein electrical energy forsupplying energy to a variable-focus optical lens (31) and/or anadjustable aperture (43) in the objective module (3) is obtained fromthe electromagnetic alternating field emitted from the near fieldcommunication unit (25) in the camera module.
 24. The method accordingto claim 21, wherein a physical quantity in the vicinity of theobjective module (3) is detected with a sensor (38) in the objectivemodule (3), and the physical quantity is used to control a function ofthe objective module (3) and/or of the camera module (2).
 25. The methodaccording to claim 21, wherein a physical quantity in the vicinity ofthe objective module (3) is detected with a sensor (38), and thephysical quantity is used to correct a dependency of the opticalproperties of the objective module (3) on this physical quantity. 26.The method according to claim 25, wherein correction data for correctingthe dependency is stored in the lens data.
 27. The method according toclaim 24, wherein electrical energy for supplying energy to the sensor(38) is obtained from the electromagnetic alternating field emitted fromthe near field communication unit (25) in the camera module (2).
 28. Themethod according to claim 21, wherein data for uniquely identifying theobjective module (3) is stored in the lens data.
 29. The methodaccording to claim 21, wherein data on the optical system of theobjective module (3) is stored in the lens data.
 30. The methodaccording to claim 21, wherein calibration data of the objective module(3) is stored in the lens data.